<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <div id="app">
        <p>{{ msg }}</p>
        <p>{{ reverseMsg }}</p>

        <button @click="reverseMsg = 'world'">修改 reverseMsg</button>
    </div>

    <script src="./js/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',

            data: {
                msg: 'hello'
            },

            computed: {
                reverseMsg() {
                    console.log('reverseMsg- Computed');
                    return this.msg.split('').reverse().join('')
                }
            },
        })
    </script>
</body>

</html>